1. Field
The following description relates to a capacitive type 6-axial force/torque sensor for measuring a moment and multi-axial force exerting on a point in space, using variations in capacitance.
2. Description of Related Art
Force exerting on a point in space may be fully described as 6 components, 3-axial force and 3-axial torque. Depending on the fields of applications, a 6-axial force sensor measuring all of the components or a 3-axial force sensor only measuring 3-axial force may be used.
A majority of multi-axial force/torque sensors may be resistive type sensors using strain gauges, and a portion of the sensors may be optical type sensors using photodiodes/phototransistors.
In the resistive type sensors, a strain gauge may be attached to a certain portion of a 3-dimensional elastic structure to measure force using variations in resistance generated in the strain gauge when the elastic structure is deformed. In the optical type sensors, force is measured by using a difference in distances between a light emitting unit (a photodiode) and a light receiving unit (a phototransistor) generated by external force.
The main drawbacks of such types may be difficulties in assembly, and the consequent increase in costs. It may be rarely feasible to automate the attachment of several strain gauges or optical devices to the 3-dimensional elastic structure in terms of operational characteristics, and the attachment may necessarily require a manual labor from a skilled person. In addition, due to the manual assembling, reactions of respective sensors may not be uniform, resulting in an increase in product quality management costs.
As a result, due to a relatively high price three or more axial force/torque sensors have not been widely used in the fields of applications requiring a force measuring sensor such as, for example, a robot.
Accordingly, the development of sensors capable of measuring multi-axial force and multi-axial torque has been required. A Related Art Document is Korean Patent Laid Open Publication No. 10-2012-0119172. All documents cited in the present disclosure, including published documents, patent applications, and patents, may be incorporated herein in their entirety by reference in the same manner as when each cited document is separately and specifically incorporated or incorporated in its entirety.